The present invention relates to a method to protect and a protective cover for swimming pools.
The present invention provides a development in the form of an improved protective cover for swimming pools, particularly as protective covers which find use as a winter protective cover for swimming pools.
In general terms, the average winter pool cover has various drawbacks that allow for such covers to permit debris or other unwanted foreign articles to pass into the pool, or that do not readily permit the passage (drainage) of the rain or melting snow that accumulated over the winter months into the swimming pool.
Many winter covers for swimming pools are composed of non-permeable generally flexible sheets of plastic material, with the cover either stretching across the opening of the swimming pool or lying on top of the pool water, in either case, the covers are anchored with weights or by tying means (ropes or other fastening devices) in which the ropes are fastened at one end to the pool cover and at the other end to an anchor or other fixed structure. Depending on the amount of precipitation, the conventional covers can be subjected to significant stress when the water or melting frozen precipitate accumulates on top of the cover, particularly at the end of a winter season. Depending on the amount of accumulated liquid, damage to the cover can occur particularly in the case where there is little or no water beneath the cover.
The requirements for swimming pool covers in terms of the material used for winter protection also requires that the material be able to stand up to the generally harsh winter elements, including the capability of being able to withstand thaw/freeze cycles, the weight of the accumulated snow on top of the cover, and the fact that debris (branches, leaves, large dirt particles etc.) can accumulate on the cover over the winter months, with a proviso that the cover not be subjected to tearing.
In the spring, it is desirable that such a cover to permit the accumulated snow to melt and drain into the pool, as opposed to trying to remove water located on the top of the pool cover. In addition, another desirable attribute would be where the cover would be able to absorb heat from the atmosphere and at the same time, reflect retained heat beneath the cover, which would allow not only for an increase in the melting of the snow but also would heat up water in the pool to further aid in the melting of snow. In addition, by permitting water to be filtered through the pool cover while providing the heating and retention properties, a cover would also desirably keep debris out of the pool during winter and during the melting of the snow.
A protective cover of this development, suitable for use in outdoor swimming pools, will thus ease the removal of debris from the cover surface after the spring melting of material on top of the cover; moreover, the cover will protect the pool liner by keeping such debris from passing through the cover.
More particularly, there is provided a protective swimming pool cover capable of absorbing light from the light spectrum in order to providing a heating effect and at the same time, the cover is provided with heat reflective properties on one side to retain heat in the pool.
According to one aspect of the present invention there is provided an improved heat absorbing winter protective covering material for swimming pools, comprising an open mesh weave of scrim material, the scrim material having warp and weft strips forming a thin layer with opposed major surfaces, wherein both the warp and weft strips are of a heat absorbing material; one of the major surfaces of the scrim material has a discontinuous coating thereon partially covering the surface; the coating being provided with heat reflecting material opposite to that of the warp and weft strips.
In a preferred embodiment of the present invention, the protective material is a continuous sheet of a one-piece xe2x80x9copenxe2x80x9d weave thermoplastic scrim material which may be provided with suitable stabilizing additives conventional in the industry as represented by ultraviolet stabilizers, extenders, anti-oxidants and the like.
Desirably, the scrim layer comprises an open-mesh weave of thermoplastic scrim material, the mesh comprising one or more substantially thin layers of intersecting strands of thermoplastic material forming a substantially closed formation when in a lay-flat condition having opposed major surfaces. Desirably, the mesh has a plurality of slits formed by intersecting strands of the open-mesh weave thereby permitting the passage of water there-through upon moisture or water pressure against the material.
The plastic material forming the strips of said composite can be made of any suitable material such as a polyolefin, the preferred polyolefin being a polyethylene or polypropylene (or a copolymer). The lace coating and the warp and weft strips can be each made of the same or a different polyolefin compatible with the polymer of the other components.
With respect to the above described field, the protective covering material includes both the warp and weft strips having heat absorptive properties, as it has been found that having both of the warp and weft strips with heat absorptive properties increases the amount of heat absorption of the product. Most preferably, the warp and weft strips form a substantially thin layer with opposed major surfaces.
Desirably, in a preferred embodiment, one of the major surfaces of the scrim has a discontinuous coating thereon, e.g. a lace coating which at least partially covers the surface, where the coating has heat reflecting properties opposite to that of the warp and weft strips.
The thickness of the scrim material used in the method of the present invention for the above field is not critical per se, as long as the product remains flexible and to the extent that water is generally able to permeate the surface through the slits or apertures; the thickness can be e.g. from 1 mil to e.g. 30 mils. or more if desired. The lace coating may likewise be relatively thin so that an overall lightweight covering can be obtained. For various types of applications, it may be desirable to provide a border surrounding the sheet material to provide an integral product.
Typically, preferred materials for the scrim layer and lace coating are thermoplastic in nature and by way of example such materials may be formed from a polyolefin such as polyethylene, polypropylene, copolymers, etc.
The coating component of the covering material of the present invention is of a discontinuous or intermittent nature, desirably in the form of a lace coating, and which forms an irregular pattern on one surface of the scrim layer. As will be described hereinafter, the lace coating can be in the form of irregular islands of coating with the islands being connected by strands or narrow strips of coating material. This coating tends to stabilize the warp and weft strips of the scrim layer and thus forms an integral product, particularly when the warp and weft strips of the scrim layer are not otherwise adhesively associated with one another. The lace coating may be formed from a heat reflective material or a material having a heat reflective component such as coloured material or reflective particles, strips etc. Desirably, the coating will cover between 5% to 80% of the scrim layer on one face thereof, most desirably 10% to 65% and preferably 15% to 50% of that surface. The coating may be applied to the scrim layer by suitable conventional techniques such as calendering, spraying, co-extrusion, or even adhesively bonded.
With respect to the heat absorbing function of either the lace coating or the warp or weft strips, such characteristics can be achieved by either selecting a thermoplastic material which has the capability of absorbing heat from the atmosphere (using selected additives in the material) or alternatively, by utilizing a colouring agent of a suitable characteristic which absorbs the energy emitted via the normal spectrum of light waves. Likewise, the other of the lace coating which is provided with reflective characteristics is produced, for example, by applying a colouring agent to the surface area from the normal light spectrum having heat specular properties such as white, silver, gold, bronze, etc., or from suitable material added thereto, for example reflective strips. Such a reflective quality of the scrim allows for heat to be reflected back toward the swimming pool or alternatively into the snow or ice built up on the cover over the winter months, helping increase the rate of melting of the accumulated snow or ice.
In another embodiment of the present invention, there is provided a method of forming a heat absorbing and heat reflective composite layer which comprises the steps of providing an open-mesh weave of scrim material in which the material has warp and weft strips forming a substantially thin layer and having opposed surfaces; wherein the warp and weft strip materials are of a heat absorbing material, and coating at least one of the surfaces of said scrim material with a coating to at least partially cover the surface, in which the coating has heat reflecting properties opposite to that of the warp and weft strips.
If desired, one or more reinforcing layers or threads may be included in the product structure where very thin covering products are used. Such a reinforcing layer or threads can strengthen the product as desired, particularly for large products covering large surfaces. For example, depending upon the desired use of the protective cover in the above noted field of the invention, such reinforcing layers can be in the form of additional reinforcing scrims incorporated into the material on one or both sides, desirably below the lace coating. Reinforcing techniques are known in various arts; they may be incorporated into the product on an in-line basis when the product is manufactured, or by extrusion, coating or like techniques. Any added reinforcing layer should not reduce the total slit availability of the material in such a manner as to close off substantially all of the slit apertures between adjacent strands; it may contribute to a reduced slit availability when this is desired to thereby provide different water permeability characteristics for different areas of the woven material.
As otherwise outlined herein, heat retention or heat absorption properties for the covering materials of the present invention, can also be varied by different means such as using concentrated or strong colours, or by including heat absorption additives in the warp/weft strips or lace coating. Thus, by way of example, reflective or absorptive particles could be included in the lace coating and/or the warp/weft strips to increase the properties desired. In addition, in the case of extruded polymeric materials for use in the lace coating, or the warp/weft strips, a co-extruded product could be employed to vary the amount of heat absorption/heat reflection characteristics of the product.
It will be obvious to those skilled in the relevant art that different degrees of heat absorption and heat radiation can be achieved for different purposes in the products of the present invention to permit products to be tailored for different applications and locations. One particular advantage of the present invention is that since only one lace coating is required, there is a savings in material, savings in the time required for producing the product, and costs are reduced.
Such a protective cover as described above finds advantageous use in both rural and urban areas where it is desirable to use the protective cover as a protective winter swimming pool cover. A protective cover utilized in such a manner is very desirable in areas where, for example, water is at a premium, and further helps reduce the cost of filling a pool with additional water in spring. Such a cover as contemplated by the present invention allows a more natural source of water to enter into the pool due to the porous mesh, while keeping large debris such as leaves, branches and other foreign particles out of the pool thereby helping protect the pool liner. Additionally, the cover of the present invention prevents light from entering the pool, which could cause algae to build up when the filtering system is not in operation, for example during the closing of the pool. Further, due to the water filtering into the pool from the cover, stagnant bodies or pools of water are reduced and therefore reduce areas for mosquitoes to thrive.
According to another preferred aspect of the present invention, there is provided a using of a protective cover having a structure generally described as a winter pool cover for a swimming pool wherein the protective cover is applied to the surface of water in a pool.
According to another aspect of the present invention, there is provided a method of forming a protective cover as a winter swimming pool as described above, as a protective winter pool cover comprising providing a protective cover, positioning the cover having a sufficient size over a corresponding swimming pool, and securing the protective cover through securement means over the surface of the pool to be covered.
In a further alternative embodiment, there is provided a heat reflecting, heat absorbing protective covering material for use as a winter protective swimming pool cover, comprising an open mesh weave of scrim material, the scrim material having warp and weft strips forming a thin layer with opposed major surfaces, where the warp or weft strips have heat absorbing properties, and one of the major surfaces of the scrim material has a discontinuous coating thereon partially covering the surface, the coating having heat reflecting properties opposite to that of the warp and weft strips.
In an alternative embodiment, the winter swimming pool protective cover includes a higher percentage of the lace coating, and desirably, a higher percentage of heat absorptive and heat reflective material in each respective element thereof as possible.